Donor–Acceptor Cyclopropanes as 1,2-Dipoles in GaCl<sub>3</sub>-Mediated [4 + 2]-Annulation with Alkenes: Easy Access to the Tetralin Skeleton
作者:Roman A. Novikov、Anna V. Tarasova、Victor A. Korolev、Evgeny V. Shulishov、Vladimir P. Timofeev、Yury V. Tomilov
DOI:10.1021/acs.joc.5b01179
日期:2015.8.21
A new process for (4 + 2)-annulation of donor–acceptor cyclopropanes (DACs) with unsaturated compounds in the presence of anhydrous GaCl3 has been developed. In this process, DACs act as sources of formal 1,2- and 1,4-dipoles to give polysubstituted tetralins in high yields and with high regio- and diastereoselectivity. Alkenes with both aryl and alkyl substituents at the double bond undergo this reaction
在无水GaCl 3存在下,用不饱和化合物对供体-受体环丙烷(DAC)进行(4 + 2)环化的新工艺已经开发出来。在此过程中,DAC充当正式的1,2-和1,4-偶极子的来源,以高收率,高区域选择性和非对映选择性提供多取代的四氢化萘。在双键上同时具有芳基和烷基取代基的烯烃同样容易地经历该反应。已经提出了最可能的反应机理。它涉及关键的1,2-偶极镓络合物的初步生成,以及随后的与烯烃的环合反应。